The present invention relates to a knee-bag module for inflating an airbag (knee-bag) in front of a leg portion of an occupant sitting in a vehicle seat with an inflator to protect the leg portion upon a vehicle collision.
In a knee-bag module formed of a knee-bag and an inflator for inflating the knee-bag, a hybrid inflator has been widely used (see Japanese Patent Publication (Kokai) No. 2003-170800). The hybrid inflator is formed of a high-pressure tank containing high-pressure gas, a gas generator, and an igniter. When the gas generator is ignited, the generated gas increases a pressure in the high-pressure tank to break a sealing member at an outlet of the high-pressure tank for ejecting a mixture of the high-pressure gas and the generated gas from a gas nozzle. The hybrid inflator can promptly inflate the knee-bag with a high gas pressure.
When the high-pressure gas is mixed with the generated gas of the gas generator, a temperature of the mixed gas decreases as opposed to a pyro-type inflator in which only reactant gas is ejected from a gas generator, thereby alleviating heat resistance of a knee-bag. However, the hybrid inflator has the high-pressure tank, thereby increasing a size and weight.
In view of the problem described above, an object of the present invention is to provide a knee-bag module having an inflator with a smaller size and lighter weight as compared with the hybrid inflator.
Further objects and advantages of the invention will be apparent from the following description of the invention.